AT&T to Offer Credits for Customers Who Swap From T-Mobile

AT&T Inc. said it will pay T-Mobile US Inc. customers as much as $450 to switch services, an unusual move as the battle between the wireless rivals heats up.

T-Mobile has launched an assault on its larger rival under Chief Executive John Legere, who has taken aim at AT&T in television ads and in comments—sometimes profane—at public events. He also has put pressure on the company by eliminating lucrative carrier standbys...